带有Lambda的C＃技巧

Question

There is some code, but the thing is very simple. I want to pass a function as a parameter, but the function is so short that it could've been created by lambda.

    class Hidden
    {
        public List<string> GetData()
        {
            return new List<string>();
        }
    }

    class Main
    {
        Dictionary<int, Hidden> dir = new Dictionary<int, Hidden>();

        public Main()
        {
            Friend f = new Friend(MethodToBeReplacedByLambda);
        }

        public List<string> MethodToBeReplacedByLambda(int id)
        {
            return dir[id].GetData();
        }
    }

    class Friend
    {
        public Friend(Func<int, List<string>> GetData)
        {
            List<string> result = GetData(4);
        }
    }

I want to delete this method

    public List<string> MethodToBeReplacedByLambda(int id)
    {
        return dir[id].GetData();
    }

And be able to pass this as a parameter by lambda. Any ideas? :D

UPDATE: I've tried:

Friend f = new Friend((int, List<string>) => dir[id].GetData());

Answer 1

Friend f = new Friend((id) => dir[id].GetData());

Answer 2

Simply create a lambda that uses the int value from the function:

Friend f = new Friend(id => dir[id].GetData())

Only the parameter names (that you use) need to be passed to the lambda, and not the return value of GetData . If you have multiple parameters, wrap them in parenthesis.